Implantable microstimulators have been developed to provide therapy for a variety of disorders, as well as other treatments. For example, implantable microstimulators can be used in neurological therapy by stimulating nerves or muscles, for urinary urge incontinence by stimulating nerve fibers proximal to the pudendal nerves of the pelvic floor, for erectile and other sexual dysfunctions by stimulating the cavernous nerve(s), for reduction of pressure sores or venous stasis, etc.
Implantable microstimulators, such as the BION® device (available from Advanced Bionics Corporation, Sylmar, Calif.), have exposed electrodes and a small, often cylindrical, housing that contains the electronic circuitry and power source that produce electrical pulses at the electrodes for stimulation of the neighboring tissue. It is often preferable that the microstimulator be as small as possible to provide stimulation to the desired tissue without substantially disturbing surrounding tissue. Therefore, the battery for the microstimulator is typically small and often rechargeable. In many instances, the battery must be recharged every day or several days, at least in part because of its small size.